Single Atom Catalysis for Furfural Conversion: Recent Advances, Challenges, and Future Perspectives.

Growing global energy demands and the continuous depletion of fossil fuel reserves have intensified interest in renewable alternatives, with biomass emerging as a promising carbon-neutral resource. Furfural (FF), a pivotal platform molecule from lignocellulosic biomass, enables the production of diverse value-added chemicals and fuels. Simultaneously, single-atom catalysts (SACs) have attracted major attention in FF valorization due to their isolated active sites, unique electronic structures, and near-complete atom utilization, enabling high activity and selectivity in complex reaction networks. This review summarizes recent advances in SAC-mediated FF upgrading. Significant progress has been made in thermochemical hydrogenation, yielding furfuryl alcohol, tetrahydrofurfuryl alcohol, and cyclopentanone derivatives. SACs have also shown strong performance in hydrogenolysis to produce high-value products such as 2-methylfuran, 2-methyltetrahydrofuran, and tetrahydrofuran. Rapid developments in reductive amination have enabled the selective synthesis of pharmaceutical-relevant amines, including piperidine, particularly using noble-metal SACs. Although less explored, the selective oxidation of FF to furoic acid and other oxygenates is also highlighted. Emerging electro- and photocatalytic FF transformations demonstrate opportunities for integrating renewable electricity or solar energy. Key challenges include improving SAC scalability and stability, tuning coordination environments, and enabling efficient coupling with green-energy inputs such as electrolytic hydrogen.